Theft-signal door knob



Dec. 11, 1923. 1,476,842

5. A. NORTH ET AL THEFT SIGNAL DOOR KNOB Filed Aug. 19. 1922 2 Sheets-Sheet 1 J'JYVEJY 0 BA. #01? 771/. L. C F/SHEL.

wwww A W Dec. 11 1923. 1,476,842

B. A. NORTH ET AL 4 THEFT SIGNAL DOOR KNOB Filed Aug. 19, 1922 2 Sheets-Sheet 2 0 37 INVENTOZZS Bf]. NORTH- J L61 R/JHEL.

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Patented Dec. 11, 1923.

UNITED STATES PATENT OFFICE.

BENJAMIN A. NORTH AND LUTHER C. RISI-IEL, OF LOS ANGELES, CALIFORNIA,

THEFT-SIGNAL DOOR KNOB.

Application filed August 19, 1922. Serial No. 582,983.

To all whom it may concern Be it known that we, BENJAMIN A.

NORTH and LUTHER C. RIsI-IEL, citizens ofpurpose of our invention is the provision of a signal of this character which is adapted to be associated with the conventional door latching means, and which operates to effect the'sounding of an alarm when the door knob is turned in either direction thereby signallingto the occupants of the house that the surreptitious opening of the door is being attempted.

Although We have herein shown and described only one form of signal embodying our invention, it-is to be understood that various changes and modifications may be made herein without departing from the spirit of the invention and the spirit and scope of the appended claims.

In the accompanying drawings,

Figure 1 is a View showing in top plan one form of signal embodying our invention in applied position with respect to a door latching mechanism.

Fig. 2 is a-sectional view taken on the line 2-2 of Fig. 1.

Figs. 3, 4, 5, 6 and 7 are sectional views taken on the lines 3-8, 4-4;, 5-5, 6-6 and 7-7 respectively of Fig. 1.

Fig. 8 is a detail perspective view of the collar shown in Fig. 2.

Similar reference characters refer to similar parts in each of the several views.

Referring specifically to the drawings, our invention, inits present embodiment, comprises a knob portion includinga section 15 of relatively heavy metal and a cover section 16, the latter constituting a bell, and adapted when in applied position to coopen ate with the section 15 in forming a portion having the general contour of the usual door knob. The section 15 is provided with an extension 17 bored to receive the useful operating shaft 18 of a door latching mech anism so as to effect an operation of the latch when either door knob is rotated.

Within the section 15 is secured a disc 19, and extending axially through the disc and into the extension 1'1 is a shaft 20 provided with an enlarged portion 21 to which is se cured one end 'ofa clock spring 22. The opposite end of the spring 22 is secured to a spring housing "23 having a hub portion 24: to which is fixed a gear 25. As clearly shown in Fig. 5, the gear 25 constantly meshes with a pinon 26 fixed to a stub shaft 27 and as clearly shown in Fig. 4, an escapement wheel 28 is fixed to the same shaft 27 upon the opposite side of the plate 19. The wheel 28 is adapted to cooperate with a pawl 29 fulcrumed at the point indicated at 30 and provided with a bill 31 which normally engages the teeth of the wheel 28. The pawl 29 is provided with a curved extension 32 carrying a pin 33 movable within a slot 34 "of the plate 19. A tapper 35 is provided with a shank 36 slidable in a bracket 37 fixed to the plate 19 and operatively connected to the pawl 29 by means of a screw 38.

The shaft or arbor 20 is extended beyond the plate 19 for connection with the section 16 of the knob portion. The section 16 is detaehably secured to the arbor 20 through the medium of a collar 39 fixed to the shaft by means'of a .pin 40. The end of the shaft 20 is recessed to threadedly receive a screw 11 which extends through the section 16 and serves to detachably secure the latter to the shaft. Between the ends of the shaft adjacent the plate 19, the shaft is provided with ratchet teeth 12 which are adapted to be engaged by a pawl 13 pivoted at the point indicated at 4. 1 upon the plate 19 and normally urged into engagement with the teeth by means of a spring 45. The arrangement of the pawl and ratchet teeth is such as to al low rotation of the shaft in one direction only for effecting a Winding of the spring 22 through the medium of the shaft. It will be understood, to effect a winding of the spring it will be necessary to rotate the section 16 clockwise as viewed in Fig. 4;, and after the spring has been wound, it will be clear that the pawl 43 engages the ratchet teeth 43 to prevent retrograde movement of the shaft.

The spring 22 is latched against actuation or unwinding through the medium of a plate 46 which, as clearly shown in Fig. 6, is mounted in a recess 17 of the section 16 for radial sliding movement with respect to the shaft 20. This plate 46 is adapted to be engaged by a cam 48 fixed to a rod or shaft 49 journaled in a suitable opening formed in the extension 17 as clearly shown in Fig. 2. The outer edge of the plate 46 at all times engages a pin 50 fixed to one end of a leaf spring 51 (Fig. 5) secured to the inner side of the section 15 and so arranged as to normally urge the pin in the direction of the plate. The pin 50 works in a slot 52 formed in the section 15, and this 7 pin is arranged to normally engage the latch pin 33 (Figs. 2 and 5) mounted on the extension 32 of the pawl 29. The arrangement of the two pins is such that they normally cooperate to maintain the pawl 29 in engagement with the escapement wheel 28 and to thus prevent rotation of the stub shaft 27 so that the spring 22 is held against expansion.

As clearly shown in Figs. 2 and 3, the shaft or rod 49 is bent at its inner end to provide a right angular expansion member 53 which is adapted to engage a bracket 54 slidably mounted upon the escutcheon plate 55 of the door. The bracket 54 is mounted for sliding movement by slotting the same as indicated at 56, and extending screws 57 through the slotwhereby the plate as a unit may be slid vertically upon the escutcheon plate to cause the same to engage or disengage the extension 53 of the rod 49.

The operation of the signal is as follows: Assuming that the spring 22 has been wound through rotation of the bell portion 16, the bracket 54 is moved to its lowermost position to engage the extension 53. With the door in closed position and the signal disposed on the inner side of the door, as will be. understood, any attempt to release the door latch by rotation of the knob portion in either direction will cause rotation of the extension 17, and as the extension 53 is held against movement, the plate 46 will be moved so that the cam 48 will function to force the plate outwardly in the direction of the pin 50. Outward or lateral movement of the pin 50 causes it to disengage the pin 33 thereby releasing the pawl 29 so that the escapement wheel 28 is free to operate. Under the action of, the spring 22, the escapement wheel 28 is rapidly rotated to effect an actuation of the pawl 29, and the latter in turn actuates the tapper to eifect a ringing of the, bell 16 thus sounding the alarm.

By virtue of the arrangement of the extension 53 and the cam 48, it will be clear that irrespective of the direction of rotation of the knob portion, the plate 46 will be ac tuated to move the pin to releasing position with respect to the pin 33 in effecting sounding of the bell 16.

If it is desired to render the signal ineffective, it will be clear that by moving the bracket 54 to its uppermost position, the cxtension 53 will be disengaged so as to be free to move with the extension 17 and the knob portion so that rotation of the latter will be ineffective to actuate the pin 50.

V hat we claim is:

1. A signal of the character described comprising a knob portion including a bell section and an extension section. a. tapper for the bell section, a spring mechanism within the extension section adapted to be wound by rotation of the bell section, an escapenient between the t apper and spring mechanism, a pin carried by the escapement, a second pin engaging the first pin to prevent movement of the escapement, a plate for moving the second pin to disengage the first pin to allow rotation of the escapement, and a cam operated by rotation of the 'knob for causing said plate to engage and move the second pin to releasing position with respect to the first pin.

2. A' signal of the character described comprising a spindle, a knob portion on the spindle including an extension section and a bell section, a tapper for the bell section, a spring mechanism within the extension. section, teeth formed on the spindle. a pawl adapted to cooperate with said teeth for preventing unwinding of the spring mechanism, an escapement between the tapper and spring mechanism, means normally acting to prevent actuation of the escapenient, and means operable by a turn of the knob portion for releasing said means.

In testimony whereof we have signed our names to this specification.

LUTHER C. RISHEL. BENJAMIN A. NORTH. 

